[1] Jauregui C, Limpert J, Tünnermann A. High-power fibre lasers[J]. Nature Photonics, 7, 861-867(2013).

[2] Villarreal-Villela A E, Cabrera L P. Monitoring the laser ablation process of paint layers by PILA technique[J]. Open Journal of Applied Sciences, 6, 626-635(2016).

[3] Oujja M, Sanz M, Rebollar E et al. Wavelength and pulse duration effects on laser induced changes on raw pigments used in paintings[J]. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 102, 7-14(2013).

[4] Wang Y B, Li J Y. Status and development tendency of high power ytterbium doped fibers[J]. Chinese Journal of Lasers, 44, 0201009(2017).

[5] Shi W, Schulzgen A, Amezcua R et al. Fiber lasers and their applications: introduction[J]. Journal of the Optical Society of America B, 34, FLA1(2017).

[6] Kliner D A V. Novel, high-brightness, fibre laser platform for kW materials processing applications[C], 11-2(2015).

[7] Wang Z Y, Chen H, Zuo T C. Influence of beam quality on laser beam behavior in laser materials processing[J]. Journal of Beijing University of Technology, 26, 89-93(2000).

[8] Qiu J L. The beam quality of high power lasers and its influences on the laser processing[J]. Laser Technology, 18, 86-91(1994).

[9] Chen H, Wu S K, Zhang Z W et al. The effect of laser beam characteristics on laser processing[J]. Optical Technique, 32, 834-837, 841(2006).

[10] Shen Q H, Wu B, Zhou D F et al. Amplified spontaneous emission of Yb3+-doped fiber laser based on MOPA[J]. Laser & Optoelectronics Progress, 50, 071402(2013).

[11] Ye Y, Wang X L, Shi C et al. Research progress in high power ytterbium doped fiber laser oscillator[J]. Laser & Optoelectronics Progress, 55, 120006(2018).

[12] Richardson D J, Nilsson J, Clarkson W A. High power fiber lasers: current status and future perspectives[J]. Journal of the Optical Society of America B, 27, B63-B92(2010).

[13] Huang L, Ma P F, Meng D R et al. Monolithic high-average-power linearly polarized nanosecond pulsed fiber laser with near-diffraction-limited beam quality[J]. High Power Laser Science and Engineering, 6, e42(2018).

[14] Yu H L, Tao R M, Wang X L et al. 240 W high-average-power square-shaped nanosecond all-fiber-integrated laser with near diffraction-limited beam quality[J]. Applied Optics, 53, 6409-6413(2014).

[15] Shi W, Fang Q, Tian X P et al. 300-W-average-power monolithic actively Q-switched fiber laser at 1064 nm[J]. Laser Physics, 24, 065102(2014).

[16] Meng K, Zhang H T, Liu M et al. 670 kW nanosecond all-fiber super-irradiation pulsed amplifiers at high repetition rates[J]. Journal of Optics, 16, 105202(2014).

[17] Zhang H W, Wang X L, Zhou P et al. 6 mJ, high-average-power, all-fiberized Q-switched fiber master oscillator power amplifier with low repetition rate[J]. Applied Optics, 51, 6933-6936(2012).

[18] Li Z B, Guo C, Li Q et al. 188 W nanosecond pulsed fiber amplifier at 1064 nm[J]. Laser Physics, 26, 075103(2016).

[19] Malinowski A, Gorman P, Codemard C A et al. High-peak-power, high-energy, high-average-power pulsed fiber laser system with versatile pulse duration and shape[J]. Optics Letters, 38, 4686-4689(2013).

[20] Wang S J, Cai Y M, Zhang Z L et al. 1000 W nanosecond pulsed laser output based on homemade 100 μm/400 μm fiber[J]. Chinese Journal of Lasers, 48, 0115001(2021).

[21] Cai Y M, Zhu Q X, Shi J H et al. High-power Yb-doped and all fiber-based nanosecond MOPA laser[J]. IEEE Photonics Journal, 14, 1533705(2022).

[22] Ye Y, Lin X F, Xi X M et al. Novel constant-cladding tapered-core ytterbium-doped fiber for high-power fiber laser oscillator[J]. High Power Laser Science and Engineering, 9, e21(2021).

[23] Zeng L F, Pan Z Y, Xi X M et al. 5 kW monolithic fiber amplifier employing homemade spindle-shaped ytterbium-doped fiber[J]. Optics Letters, 46, 1393-1396(2021).

[24] Lin X F, Ye Y, Zhang Z L et al. 2.7 kW co-pumped fiber amplifier based on constant-cladding tapered-core fiber[J]. Optical Fiber Technology, 68, 102773(2022).

[25] Ye Y, Lin X F, Yang B L et al. Tapered Yb-doped fiber enabled a 4 kW near-single-mode monolithic fiber amplifier[J]. Optics Letters, 47, 2162-2165(2022).

[26] Zhang Z L, Lin X F, Zhang X et al. Low-numerical aperture confined-doped long-tapered Yb-doped silica fiber for a single-mode high-power fiber amplifier[J]. Optics Express, 30, 32333-32346(2022).

[27] Zhu Y, Leich M, Lorenz M et al. Yb-doped large mode area fiber for beam quality improvement using local adiabatic tapers with reduced dopant diffusion[J]. Optics Express, 26, 17034-17043(2018).

[28] Leich M, Kalide A, Eschrich T et al. 2 MW peak power generation in fluorine co-doped Yb fiber prepared by powder-sinter technology[J]. Optics Letters, 45, 4404-4407(2020).